|  | 1.6 |
The Transport Layer of the OSI Reference Model
| 1.6.4 | Why is a buffer used in data communications
When data transfer is in progress, congestion can arise for two different reasons. First, a high-speed computer might be able to generate traffic faster than a network can transfer it. Second, if many computers simultaneously need to send datagrams to a single destination, that destination can experience congestion, even though no single source caused the problem. When datagrams arrive too quickly for a host or gateway to process, they are temporarily stored in memory. If the traffic continues, the host or gateway eventually exhausts its memory and must discard additional datagrams that arrive. Therefore an indicator acts like a stoplight and signals the sender to stop sending data. When the receiver can handle additional data, the receiver sends a "ready" transport indicator, which is like a "go" signal. When it receives this indicator, the sender can resume segment transmission.